Mechanism to secure stereotype printing plates and in printing plates for use with that mechanism



Dec. 30, 1952 J. o. CRABTREE r-:TAL 623,462

MECHANISM TO SECURE STEREOTYPE PRINTING PLATES AND IN PRINTING PLATES FOR USE WITH THAT MECHANISM Filed Jan. 1o, 195o 2 SHEETS-SHEET 1 l 'n r"" O 2 u a O 23/ f o O 5 27 5 v O o /6 7 /2 f3 .ZZ f' 4 Z 1i f J /2 L Dec. 30, 1952 J. o. CRABTREE ETAL 2,623,462

MECHANISM TO SECURE STEREOTYPE PRINTING PLATES AND IN PRINTING PLATES FOR USE WITH THAT MECHANISM NVENTORS Ma@ mahmw ATTORNZY Patented Dec. 30, 1952 MECHANISM "TO SECURE 'STEREOTYPE APRINTING PLATES AND IN `PRINTING APLATES FR TUSE WITH THAT MECH- `AN ISM John Oldfield Crabtree and .-Charles William Marshall, London,Eng1and, assignors to R. Hoe & Co. Inc., New York, N. Y.,.a corporation of New York Applicationlanuaryxll), 1950, Serial No. 137,861 In Great :Britain January l0, (1949 This invention relates `to mechanism to secure stereotype printng yplates to the cylinders ,of rotary printing machines and to stereotype Aplates themselves.

The invention is concerned with the type of holding `mechanism which is arranged to tension the 'plate from its ends circumferentially of the cylinder'for which purpose the undersurfaceof the plateisformedinzone or other fashion to be `engaged by clamps along a line parallel with its ends and which are `movable in the .circumferential sense.

In `a large Vclass of rotary `printing machines using such plates, the plates often extend over a considerablearc say about 180 ofthe cylinder. To afford the desired `purchase of the clamps on the plate, `it is necessary to provide both the plate -and `the clamps with undercut surfaces which have to be moved clear Aof one another when the plate is presented to the cylinder Afor the `plating `operation and Whentheplate -is to 'be removed from the v'cylinder'.

The main Vobjectl of `this invention 4is'toiprovide a plate-holding-mechanism and aplatewhich will facilitate the fitting to and removal of the'plate This lObjectis achievedbroadly stated 'by providing the clamp for at least one `Yof 4the `ends of the plate Ywithplate-engaging surfaces 'which are spaced apart 4in the longitudinal sense 'of the cylinder and by forming the plate with 'correspondingly spaced surfaces, the spacing 0f the surfaces yon the 'clamp and the -plate Jbeing Asuch that those on `the plate `.can interealate Vthose #on theclamp: with this arrangement, ltheplate can readily bepresented so to speak, face-onto the cylinder in the intercalating relationship `and then r slid longitudinally of the cylinder `:to bring its clamping'surfacesinto operative .register with the clamping :surfaces fof the lclamp which can then be pperated :to efiect the :ides'ireditensioning of the plate sabout the :cylinder` `The :converse operation -is carried out ,when the :plate fis pto :be removed.

When a plate `is'to :be engaged only atgits leading and trailing ends, iit would be suiiicient :for the clamp and the plate to be `formed in vaccord" ance with this invention wat only one fend al though `if desired .both the leadingandrtrai-ling ends and theirclampscould be so formed.

Thelinventionis concerned also `withtl'ieuse of a very common'type of printing plate having at (01. lOl-37S.)

its under `orconeave surface circumferential ribs, and theinvention contemplates forming in such ribs undercut recesses tto form the .clamping sur.- faces to be engaged in the region of the leading .and trailing edges `by clamps which can be moved to tension the plate circumferentially of fthe cylinder. When the `clamping mechanism is con.- structed according .to the feature of this invention as `first referred to (i. e. with clamping surfaces `arranged tointercalate those on the plate) .then the clamp would be formed `With .clamping surfaces which are spaced `apart to enable the circumferential ribs to `be passed between them, `the plate then being moved longitudinally to cause `the surfaces on the clamp to pass into the re.-

cesses inthe ribs.

The use of the ribs to aifordthe desired clampengaged surface enables a plate as produced joy the widely used plate casting equipment to1be modified .for the purpose of the present invention 'by a simple `machining operation .hy which the recesses are cut transversely in the circumferential ribs as produced by those machines.

The clamps for 'both the leading ,and trailing edges of such aplate could'be formed ,merely by bars having undercut or hooked-shaped faces and extending longitudinally .of the cylinder and one at least of thesebars iis rmovableinthe circumferential sense of the cylinder'to-tensionand release a plate.

One or both of the pars 4isn-etched at a'pitch related 'to the pitch of `the Vcircmnferential Jribs on vthe plate, the notches being ldiinensionedto receivethe ribs whereafter as has-been described theplate `isvmoved longitudinallylto ycarry the end undercut Wallsofthe recesses formed in theribs into register with the projections fleft fbetween the `notches on the bar.

The invention is illustratedin/:the accompany, ing .drawings as .applied ,to the plate `securing lmechanism xforming :the gsubject of the pending application `Serial No. 137,862. lIn-the drawings, Figurel is an end elevation` of -aprintinglcylinder having a printing platesecured to it, Figurefz is a longitudinal sectionalelevation on thefline-I-I, Figure 1, showing only part of -the total length of a printing cylinder, Figure 3` is a `perspective View showing part ,of `a printingcylinder anda printing plate preparedfor use with theclamping mechanism, Figure eis alocal elevationlook- "50 ving in the direction of the arrow IV, Figure 1, the

figure being partly in section with parts broken away, and Figure 5 a section on the line V-V, Figure 4.

Reference will rst be made to the plate securing mechanism so that the purpose of the present invention sha1 be more readily understood.

Referring rstly to Figures 1 and 3, I indicates a printing cylinder and 2 a stereotype printing plate tted thereto, the plate having at its under surface (i. e. its concave surface) a series of circumferential ribs 3. These ribs are cut away to form recesses 4 and 5 near the longitudinal edges of the plate and to leave at the longitudinal centre of the plate a series of projections 6, the Walls of the recesses 4 and 5 and of the projections being undercut or sloped.

The cylinder I is fitted with clamping mechanism comprising intermediate clamps to engage or grip the projections 6 and clamps (or hooks) to engage in the recesses 4 and 5 to tension the plate circumferentially about the cylinder from the gripped projection 6.

The intermediate clamp comprises a xed bar I having an upstanding hook-shaped part 8 to engage one undercut wall of the projection 8, a movable bar 9 also having an upstanding hookshaped part I to engage the other undercut wall of the projection 5. The xed bar 'I is disposed towards the trailing end of the plate I (it being assumed that the cylinder I will rotate in the direction of the arrow l1 in Figure 1) While the movable bar 9 is disposed towards the leading end, and this movable bar is arranged to be operated to move in a direction towards the trailing end of the plate and hence towards the fixed bar 'I and so, conjointly with the fixed bar, to embrace and grip the dovetail projection This results in anchoring the plate to the cylinder I against both circumferential and radial movement.

Each of the end clamps is similar and each comprises a bar I2 having hook-shaped projections I3 to engage the undercut walls of abutments formed by the recesses 4 and 5 at the leading and trailing edge respectively. Each bar is movable in the generally circumferential sense of the cylinder towards and away from the intermediate clamp, 8, I9.

Assuming that the intermediate clamp has been operated to take hold of the projection 6 at the center of the plate 3, the end clamp bars I2 at the leading and trailing edges of the plate are operated to strain or tension the plate away (in each direction about the cylinder)A from the intermediate clamp which provides a xed reaction point to the tensional strain.

Considering now the present invention it will be clear that in fitting a plate 2 to a cylinder I the undercut walls of the recesses 4, 5 have to pass over the hooked ends I3 of the clamping bars I2, and the purpose of the present, invention is to facilitate this operation especially in those cases in which the plate 2 extends over a substantial arc of a circle.

For the purpose of this invention, the clamping bars' I2 instead of being formed with a continuous hook surface are formed with spaced hook portions I3 which leave gaps 30. The gaps have a pitch corresponding to the pitch of the ribs 3 of the plate 2. With this arrangement, the plate I can be presented face-on to the cylinder with the gaps 3E! in register with the ribs 3 as shown in Figure 2. The plate is then slid longitudinally up to a margin ring 3I so as to bring the hook portions I3 left by the gaps 3D into longitudinal register as shown in Figure 4 with the ribs 3 or more precisely with the abutments formed by the recesses in the ribs.

It is to be pointed out that the intercalating arrangement of this invention is not limited in its application to the plate clamping arrangement shown in the drawings: i. e. it is not limited to an arrangement employing the intermediate plate clamp l, 9 for it could be applied to an arrangement employing only the end components I2. However, when such a central clamp is used it is not necessary to form the clamp bar 9 in this way for the projections 6 on the plate can pass straight in between the hooks 8 and I0 when the hook I0 is retracted.

It is also to be observed that while it is preferred to arrange both components I2 with the gaps 30, it is not essential for more than one of them so to be formed. In such a case, the recesses 5 at one edge of the plate 2 could be hooked under the ungapped hook I2 and then rocked to bring its other recesses 5 into the gaps 30 of the other component I2 and then slid longitudinally.

The various operating bars are arranged for actuation from the ends of the cylinder I and the actuating mechanism would include a spring or springs which would operate to urge the clamps to be spring held against their respec- Y tive surfaces on the plate.

In the arrange-ment shown in the drawing and especially in Figures 2, 4 and 5, the two clamping bars I2 and the clamping bar 9 are similar as regards their operating mechanism and in Figures 2, 4 and 5 this is indicated by the combined references I2 (9) and I3 (I0).

Each of the bars is flanged at I4 and is se-` with these surfaces are other Wedge surfaces I8 on an operating bar I9 which is slidable longitudinally in the recess I6. Hence by moving the bar I' forwards or backwards, the clamping bars 9 and I2 are caused to moved backwards or forwards tangentially of the cylinder so as either to thrust the hooks Ill or I3 against the abutment surfaces on the plate or to retract them from those surfaces.

The wedges would be arranged at such an angle as to be irreversible so that the operating bars cannot be reversed by reaction from the plate 2.

In order that clamping bars I2 shall be spring pressed so as automatically to take-up any increase in the arcuate length of the plate and also in the case of the bars 9 and I2 to accommodate for dierences in various plates, the operating bars I9 are bored at one end to receive a coil spring 20 which acts and reacts between the bar I9 and a plunger rod 2l which is pivotally connected at 22 to a link 23. The link is pivoted at 24 to an operating bell crank 25 pivoted at 26 in a bracket 2l secured to the end of the cylinder I, the bell-crank having an operating arm 28. When the bell-crank lever 25 is rocked, the corresponding bar I9 is moved backwards or forwards. When, in moving forwards, the wedges I8 thrust the hooks against the abutments on the plate I so that the hooks meet with resistance, the continued movement of the bell-crank 25 causes the spring 2B to be compressed and to accepta" urge the hooks forward by their spring pressure. The `arrangement of the pivoted centres 22, 24 and 26 is such that the final movement of the bell-crank 2'5 carries the centre 24 past the straight line joining the centres 22 and 26, i. e. it carries the bell-crank to an `over--centre position so that the spring 2d now reacts to hold the bell-crank 28 locked in its clamping position and at the same time to urge the hooks forwardly against the plate.

The pivotal connection 22 between the link 23 and the bar I9 is effected through a slo-t 29 in the bar I9. The slot enables the bar I9 to have freedom to be urged forward by the spring 2l! without restraint by the operating bell-crank and (when the bell-crank is reversed to release the bar I9) the pin travels to the end of the slot and then positively moves the bar.

By reason of the irreversiblity of the bar 9 of the intermediate clamp, a reaction is provided against which the action of the spring of the clamp for the leading end of the plate can exert circumferential tension in a direction towards the leading end of the plate.

We claim:

1. In combination a printing cylinder, a curved stereotype printing plate having ribs on its concave surface and undercut abutments formed in the ribs at the trailing and leading edge regions of the plate, plate clamping mechanism comprising angularly separated plate clamps having hook shaped members projecting beyond the periphery of the cylinder to engage respectively the abutments on the plate, and means to move the clamps relatively to tension the plate about the cylinder, said members and the corresponding abutments having cooperating engaging surfaces of less width than the longitudinal spacing between said surfaces, so that the surfaces on the plate can be passed between the surfaces on the clamp and the plate can then be moved longitudinally of the cylinder into register.

2. In combination a printing cylinder, a curved stereotype printing plate having ribs on its concave surface and angularly separated undercut longitudinal abutments formed in the ribs, plate clamps having hook shaped members projecting beyond the periphery of the cylinder to hold a plate to the cylinder by engaging with the abutments, and means to move angularly the said clamps relative to one another to ten-sion the plate between them, said members and the corresponding abutments having cooperating engaging surfaces of less width than the longitudinal spacing between said surfaces, so that the surfaces on the plate can be passed between the surfaces on the clamp and the plate can then be moved longitudinally into register therewith.

3. In combination a printing cylinder, a curved stereotype printing plate having peripherally eX- tending ribs on its concave surfaces with continu-ous channels cutting across the ribs near the trailing and leading edge regions of the plate thereby forming clamping abutments, plate clamping mechanism in the cylinder and comprising angularly separated plate clamps having abutment engaging members projecting beyond the periphery of the cylinder to engage respectively the abutments on the plate, and means to move the clamps relatively to tension the plate about the cylinder, the said moving means comprising an operating member, and spring means through which the member operates to impart relative tensioning movement to the clamps, and said members and the corresponding abutments having *cooperating engaging 'surfaces of :less` width than the longitudinal spacing between .saidv surfaces, so that the abutment surfaces on the plate can be passed between the abutment engaging members on the clamp, and the plate then be moved longitudinally into register.

4. In combination a printing cylinder, a curved stereotype printing plate having peripherally extending ribs on its concave surface with a continuous channel cutting 'across the ribs near each straight edge of the plate and thereby forming ,a clamping abutment, plate clamps Lin the cylinder having abutment engaging members projecting beyond the periphery of the cylinder to hold a plate thereon by engaging with the abutments, and means to move the said clamps relative to one another to tension the plate between them, the said moving means comprising an operating member, and spring means through which the member operates to impart relative tensioning movement to the clamps, the said members and the corresponding abutments having cooperating surfaces of less width than the longitudinal spacing between said surfaces, so that the abutment surfaces on the plate can be passed between the abutment engaging members on the plate and tle plate then moved longitudinally into reg- 1s er.

5. In combination a printing cylinder, a curved stereotype printing plate having peripherally extending ribs on its curved surface with a continuous channel cutting across the ribs near the trailing and leading edge regions of the plate thereby forming clamping abutments, plate clamping mechanism in the cylinder and comprising angularly separated plate clamps having abutment engaging members projecting beyond the periphery of the cylinder to engage respectively the abutments on the plate and means to move the clamps relatively to tension the plate about the cylinder, the said moving means comprising an operating member, an irreversible device to transmit plate tensioning operation to the plate clamps, and spring means through which the operating member operates the irreversible device, and at least one of the clamps and the corresponding clamping abutments having cooperating surfaces of less width than the longitudinal spacing between said surfaces, so that the abutment surfaces on the plate can be passed between the abutment engaging members on the clamp, and the plate then be moved longitudinally into register.

6. In combination a printing cylinder, a curved stereotype printing plate having peripherally eX- tending ribs on its curved surface with continuous channels cutting across the ribs near each straight edge of the plate and thereby forming clamping abutments, plate clamps in the cylinder having abutment engaging members projecting beyond the periphery of the cylinder to hold a plate thereon by engaging with the abutments, and means to move angularly the said clamps relative to one another to tension the plate between them, the said moving means comprising an operating member, an irreversible device to transmit plate tensioning operation to the plate clamps, and spring means through which the operating member operates the irreversible device, and at least one plate clamp and its corresponding abutments having cooperating surfaces of less width than the longitudinal spacing between said surfaces, so that the abutment engaging members on the clamp can be passed between 7., the surfaces on the plate and the plate then Number moved longitudinally into register. 1,790,665 JOHN OLDFIELD CRABTREE. 1,840,320 CHARLES WILLIAM MARSHALL. 2,086,145 5 2,131,891 REFERENCES CITED 2,236,230 The following references are of record in the 2,474,127 le of this patent: 2,474,889

UNITED STATES PATENTS Number Name Date lo Number 159,172 Forsyth Jan. 26, 1895 419,738 178,229 Bruen June 6, 1876 8 yName Date Hubbard Feb. 3, 1931 Jordnoy Jan. 12, 1932 Wood July 6, 1937 Huck Oct. 4, 1938V Worthington Mar. 25, 1941 Tollison -et al. June 21, 1949 Crafts July 5, 1949 FOREIGN PATENTS Country Date Great Britain 1 Nov. 19, 1934 

